In many surgical procedures, it is often necessary to ligate a plurality of vessels within the surgical site. The vessels may be severed downstream of the ligated portion. In some instances, the vessels may be ligated in spaced apart areas and the portion of the vessel between the ligations removed. The purpose of ligating vessels is to maintain the surgical site free from an excess of blood and reduce blood loss in the patient. Also in certain surgical procedures where tumors and the like are to be removed, the tumor or organ may have to separated from certain vessels. Before separating, the vessels are ligated. Once a blood vessel is completely shut off, hemostatsis, that is, the natural closing of the end of the vessel so as to stop blood flow, will occur in several days depending on the vessel. The body, in the meantime, will continue to allow blood flow around the ligated area through appropriate capillaries and secondary vessels with the natural physiological function of the body enlarging these bypass vessels until adequate blood flow is obtained. Hence, when ligating the vessel, there should be positive stoppage of the blood flow in the main vessel. Failure to provide complete stoppage may cause blood loss in the patient and may also disrupt the natural hemostasis and concurrent manufacture of new paths of blood flow in the patient.
In the past, this closing of the vessel was usually accomplished using ligatures; i.e., filaments or threads which the doctor tied around the vessel to be closed. This is a time consuming process and one wherein positive closure of the vessel is not always accomplished. In recent years, hemostatic clips have replaced ligatures in surgical procedures to close blood vessels and other fluid ducts. Very often these hemostatic clips are narrow U or V shaped strips formed of tantalum or stainless steel which are capable of being deformed and possess sufficient strength to retain the deformation when clamped about a blood vessel. The closing force is developed by the deformation of the metal. We know of no polymeric materials that can be used in this type of clip. The polymeric materials are either too resilient and will not maintain the closed position or too brittle and break when deformed to the extent required to surround and close a vessel.
In co-pending commonly assigned patent application Ser. Nos. 276,131 filed June 22, 1981 and 282,165 filed July 31, 1981, there are disclosed hemostatic clips made from bio-compatible polymeric materials which are absorbable or nonabsorbable in body tissue. These clips comprise a pair of leg members connected at their proximal ends by a resilient hinge section and terminating at their distal ends in a locking latch means. The distal end of one of the leg members comprises a deflectable hook section. The distal end of the other leg member is configured to be engaged by the hook section and the leg members are pivoted about the hinge to close the clip about a blood vessel. These clips have been found very satisfactory for ligating blood vessels. However, there are certain polymeric materials that do not have the required resiliency to be used in such clips. For example, it is very difficult to make lactide and glycolide polymers and copolymers which have sufficient resiliency to produce a resilient hinge on a clip that will function to maintain a blood vessel closed. Also, these polymers are relatively brittle so that they cannot be deformed about a blood vessel similar to the way a metal clip is used to close a blood vessel.
What we have discovered is an improved ligating clip structure which allows the clip to be made from substantially non-resilient and non-deformable materials, yet produces a clip which adequately closes a blood vessel for a sufficient period of time to provide hemostatsis and makes a suitable hemostatic clip.
Our new clip is configured to be readily and easily manipulatable so that the clip may be opened and closed about a blood vessel with a minimum of manipulative actions. Furthermore, our new clip may be manufactured using simple molding techniques well known in the art and is inexpensive to purchase.